Hambro Composite Floor System

More than
just a floor

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Hambro Composite Floor System

With the Hambro product, Canam meets the needs of residential and multi-residential markets by providing owners, real estate developers and general contractors with optimized construction solutions.

Canam offers an array of structural components, including the Hambro D500 composite floor system, a composite girder and a transfer slab system, which can be combined in order to design better adapted and more functional buildings.

Hambro D500 : More than just a floor

The Hambro D500 composite floor system is your cost-effective answer to solid, reliable elevated slabs supported by proven floor joists. Compatible with all traditional structural systems, the Hambro D500 floor combines the flexibility of the D500 joists with the strength of a reinforced concrete slab.


Fast and easy to install, the Hambro floor provides many benefits:

  • Maximum duct opening for easy installation of HVAC, electricity and plumbing systems
  • Less concrete and reinforcing steel than conventional slabs minimizing costs and saving on-site construction time
  • Long span without shoring to reduce number of load-bearing walls
  • Rigidity and strength of the steel/concrete design
  • Fire-resistance rating of up to 3 hours: Hambro system complies with UL/ULC/cUL ratings
  • Acoustical properties: Hambro system meets STC 57 / IIC 30 rating requirements
  • Versatile: compatible with all traditional structural systems
  • Reusable plywood forms
  • Optimum service: fast and dependable deliveries, project management, technical assistance, value engineering, design plans


By combining Hambro steel joists with the poured concrete, the system forms composite T-beams that are integrated in the transversally reinforced continuous slab. The bottom chord acts as a tension member during the concreting process while the web systems, which are made from bent rods, serve to resist vertical shear.

The top chord withstands compressive action during the non-composite stage and subsequently functions as a continuous shear connector between the steel and concrete through adhesion and friction. The slab is reinforced with welded wire mesh.

The reinforced concrete slab also contributes to the transfer of horizontal loads (wind, seismic activity) and acts
to stiffen multistory buildings.


The ease and speed of installing the Hambro D500 floor system eliminates the need for skilled trades.


The joists are placed on the walls or beams and positioned in compliance with the shop drawings issued for construction by Canam.
The joist connection methods are also shown on the Canam drawings.


The rollbars are designed to support the plywood forms, concrete construction load.
When rotated and locked into the notches in the top chord, the rollbars lock the joists in place while providing lateral and torsional stability to the joists.

Bottom chords are fabricated with clips to accommodate rollbars if temporary bridging is needed during
the pouring process. Generally, no permanent bridging or shoring is required unless specifically noted.


Together, the plywood and the rollbars form a rigid diaphragm during construction, providing a safe platform for workers.
The Hambro system uses standard 4 ft x 8 ft x ½ in.2 (1,200 mm x 2,400 mm x 13 mm2) plywood sheets.


Welded wire mesh serves as the standard catenary for the slab. Standard 8 ft x 20 ft (2,400 mm x 6,100 mm) sheets of mesh
are easily placed over the top chords of the Hambro joists. The top chord acts as a high chair.


When pouring and finishing a Hambro slab, it is not necessary to complete the entire deck in a single pour. In the event that the pour is interrupted parallel to the joists,
the joint should be midway between the joists, but never less than 6 in. (152 mm) from the top chord in order to ensure composite action.


When the concrete attains a cylinder strength of 500 psi (3.5 MPa), the rollbars and plywood forms can be removed.
When the concrete attains a cylinder strength of 1,000 psi (7 MPa), the floor is ready but care must be taken not to surpass the admissible loads for the specified capacity.

For longer spans

The Hambro girder act as a principal beam supporting the Hambro D500 joists wich are installed perpendicular on each side. Developed for the multi-residential and commercial markets, the Hambro composite girder offers greater spans than the conventional steel girder while maintaining a minimum depth to adapt to the Hambro joists.

Designed to address the need for longer spans and better ductability, the Hambro composite girder is composed of a top and bottom chord, each made of two angle sections.

  • The web system consists of vertical and diagonal members.
  • The top chord S connector closes the opening between the two angle sections.
  • In addition to the S connector and where necessary for shear requirements can be shop-installed on the girder between the Hambro joists.


Composite action between the slab and the girder

Utilizing a concrete slab in the overall design of the Hambro girder allows a better span-to-depth ratio than that of a conventional girder. Although a ratio between 24 and 27 generally represents an efficient and economical solution, a composite product can reach a ratio of up to 30. For example, in the case of a 30-ft girder, the optimum depth is approximately 14 inches while the minimum depth is 12 inches.

Duct openings

Due to the composite design of the Hambro girder, the top and bottom chord members are smaller than those of a conventional girder. This provides for wider openings between the members. The vertical members of the Hambro girder are aligned with the joists bearing on the top chord, maximizing the size of the openings between the diagonal members and the bottom chord.

Fire resistance rating tested to ULC and UL standards

Composite Hambro girders form an integral part of the composite Hambro floor system and therefore can reach a fire resistance rating of up to 3 hours, depending on the type of ceiling used

Reduced number of columns

Composite Hambro girders are ideal for floors requiring long spans since fewer columns are utilized. The optimum span of a composite Hambro girder ranges between 25 and 35 ft.

Camber designed for the dead load of wet concrete

Hambro girders and joists, designed with a camber according to the dead load of wet concrete, become level after the pour. This provides the flexibility to install the ceiling directly beneath the bottom chord in accordance with ULC and UL specifications.

Can be designed to carry multiple floor loads

With a concrete slab and steel members incorporated into its design, the composite Hambro girder can be designed to carry multiple floor loads. Contact us for more information.

Shear connectors

The longitudinal shear that occurs between the concrete slab and the steel girder is due to the action of the following four elements:

  • The joist shoes welded at regular intervals to the girder. This concept, patented under the name Shear Shoe, utilizes a secondary structural element (joist) to create the longitudinal shear of a primary structural element (girder).
  • The anchorage created by the end plate welded at each end of the girder. The horizontal force is associated with the resistance of the concrete.
  • The bond friction that occurs between the joist top chord S and the concrete slab.
  • The additional connectors used to support heavy loads (U-shaped steel channels welded to the girder at regular intervals). These U-shaped channels were developed in collaboration with the Centre de recherche industrielle du Québec (CRIQ) and are always installed in pairs (one welded on the top of each angle of the top chord member).
Connections to effectively transfer shear loads50

Connection details

D500 joist and girder-to-wall connection.

D500 joist and girder-to-concrete column connection.

D500 joist and girder-to-steel column connection.

Girder-to-girder connection.

The strength of composite action

The Hambro transfer slab the practical and smart alternate design to conventional podium concrete slabs. The transfer slab is a floor system that transfers the superimposed loads from the structural building frame above the slab to the columns, walls and foundations below.

Smart alternative to conventional concrete podium slabs50

The Hambro transfer slab designed by Canam is composed of Hambro joists and girders in composite action with a concrete slab, which makes it easy to install.


  • Is ideal for slabs above garage parking levels, plazas in mixed-use multi-residential development projects.
  • Requires less concrete and reinforcing steel, reducing job-site time and costs.
  • Can be engineered and designed to support multiple floor and wall loads from above.
  • Offers strong transitions from load-bearing construction to columns, walls and foundations below.
  • Enables maximum usable space below the slab for easy integration of mechanical, electrical and plumbing systems.
  • Has high fire rating and low sound transmission qualities.
Hambro D500 on concrete walls

Hambro D500 on concrete walls

3D animation

ICF walls

ICF walls

Hambro D500 on ICF walls
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Wood walls

Wood walls

Hambro D500 on wood walls
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Steel frame walls

Steel frame walls

Hambro D500 on steel frame walls
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Masonry walls

Masonry walls

Hambro D500 on masonry walls
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